The objective of this proposed project is to elucidate the mechanisms that control morphogenesis and differentiation during lens development. It has been shown by immunofluorescence that lens development involves the co-ordinated expression of crystallin genes. Experiments have shown that the neural retina, which forms from the inner layer of the optic vesicle, induces the lens epithelial cells to synthesise Beta- and Gamma- crystallins and elongate. The nature of the neural retina factor(s) is not nown. Nor is it nown if the same retinal factor(s) induces lens morphogenesis and Alpha- crystallin synthesis. Alternatively some or all of these processes may be controlled by separate environmental cues. The first step in the proposed work will be to characterise and isolate the lens fibre inducing factor(s) from the neural retina. This will be carried out in explant cultures. Retina conditioned medium will be fractionated by ultracentrifugation and gel chromatography and the fractions tested for their fibre inducing properties. Once this factor(s) has been isolated antibodies will be raised against it and immunohistsochemical methods used to localise it. In addition I125 and ferritin labelling will be used to follow the inducer during its interaction with the lens cells. The ability of the neural retina factor(s) to initiate lens morphogenesis and Alpha- crystallin synthesis will also be tested 'in vitro'. To study mechanisms controlling lens morphogenesis antibodies will be raised against actin and tubulin and immunofluorescence methods used to study changes in microfilaments and microtubules. it will be possible to interfere with these changes in explant cultures and determine if subsequent patterns of morphogensis and cytodifferentiation such as crystalin synthesis are influenced